title: Response of cricopharyngeus muscle to esophageal stimulation by mechanical distension and acid and bile perfusion.
abstract: OBJECTIVE
  The aim of this study was to identify the response of the cricopharyngeus muscle (CPM) to esophageal stimulation by intraluminal mechanical distension and intraluminal acid and bile perfusion.
  
  
  METHODS
  In 3 adult pigs, electromyographic (EMG) activity of the CPM was recorded at baseline and after esophageal stimulation at 3 levels: proximal, middle, and distal. The esophagus was stimulated with 20-mL balloon distension and intraluminal perfusion of 40 mL 0.1N hydrochloric acid, taurocholic acid (pH 1.5), and chenodeoxycholic acid (pH 7.4) at the rate of 40 mL/min. The EMG spike density was defined as peak-to-peak spikes greater than 10 microV averaged over 10-ms intervals.
  
  
  RESULTS
  In all 3 animals, the spike density at baseline was 0. The spike densities increased after proximal and middle distensions to 15.2 +/- 1.5 and 5.1 +/- 1.2 spikes per 10 ms, respectively. No change in CPM EMG activity occurred after distal distension. The spike density following intraluminal perfusion with hydrochloric acid at the distal level was 10.1 +/- 1.1 spikes per 10 ms. No significant change in CPM EMG activity occurred after acid perfusion at the middle and proximal levels. No change in CPM EMG activity occurred after intraluminal esophageal perfusion with either taurocholic acid or chenodeoxycholic acid.
  
  
  CONCLUSIONS
  Proximal esophageal distension, as well as distal intraluminal acid perfusion, appeared to be important mechanisms in generation of CPM activity. Bile acids, on the other hand, failed to evoke such CPM activity. The data suggest that transpyloric refluxate may not be significant enough to evoke the CPM protective sphincteric function, thereby placing supraesophageal structures at risk of bile injury.
authors.affiliation: Section of Otolaryngology-Head and Neck Surgery, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
authors.forename: Natalya
authors.initials: N
authors.lastname: Chernichenko
authors.forename: Jeong-Soo
authors.initials: JS
authors.lastname: Woo
authors.forename: Jagdeep S
authors.initials: JS
authors.lastname: Hundal
authors.forename: Clarence T
authors.initials: CT
authors.lastname: Sasaki
mesh_terms: D000818:Animals; D001647:Bile Acids and Salts / Q000494:pharmacology; D004576:Electromyography; D004947:Esophagus / Q000187:drug effects / Q000502:physiology*; D006851:Hydrochloric Acid / Q000494:pharmacology; D008297:Male; D010477:Perfusion; D010609:Pharyngeal Muscles / Q000502:physiology*; D013552:Swine
chemical_list: D001647:Bile Acids and Salts; D006851:Hydrochloric Acid